Closure devices are known in a variety of forms and are usually made of a plastics material. A base element typically comprises a device for fastening the base element to an opening of the container, for example to a bottle neck, an internal thread being able to be provided, for example, so that the closure device can be screwed onto the bottle neck.
Extending from the base element there is frequently a dome-shaped spout, which can be enclosed by the mouth of the drinker, for example, including when drinking from the container.